When the weather starts to cool off, you might be thinking about how you’ll take full advantage of your heating and cooling. After all, HVAC costs can add up to a significant piece of your monthly electric bill. To learn new ways to save, some owners look closely at their thermostat. Could there be a setting they can use to boost efficiency?

The bulk of thermostats come with a ‘Fan’ or ‘Fan On’ setting. But if the fan is running during a normal cycle, what will the fan setting offer for an HVAC system? This guide should help. We’ll review just what the fan setting is and when you can use it to cut costs in the summer or winter.

How Do I Access the Fan Setting on My Thermostat?

For the bulk of thermostats, the fan setting means that the HVAC blower fan remains on. Some furnaces may continue to run at a low level in this setting, but for the most part heating or cooling isn’t being produced. The ‘Auto’ setting, conversely, will start the fan through a heating or cooling cycle and switch it off once the cycle is complete.

There are advantages and disadvantages to trying the fan setting on your thermostat, and whether you do or don’t {will|can|should]] depend on your unique comfort needs.

Advantages to switching to the Fan/On setting:

  • You can keep the temperature in every room more balanced by enabling the fan to keep running.
  • Indoor air quality will be highest because steady airflow will keep passing airborne contaminants into the air filter.
  • Fewer start-stop cycles for the HVAC fan helps expand its life span. Since the air handler is typically a component of the furnace, this means you could avoid needing furnace repair.

Disadvantages to utilizing the Fan/On setting:

  • A constant fan can increase your energy costs somewhat.
  • Continuous airflow could clog your air filter soon, increasing the frequency you’ll need to replace it.

{Choosing Between|Should My Thermostat Be on|Which Setting for My Thermostat? Fan or Auto in Summer/Winter

During the summer, warm air may stick around in unfinished spaces including the attic or an attached garage. If you leave the fan on, your HVAC system may gradually move this warm air into the rest of your home, compelling the HVAC system to run longer to maintain the desired temperature. In serious heat, this may lead to needing AC repair more quickly as wear and tear grows.

The reverse can happen during the winter. Cooler spaces like a basement will hold onto cooler air, which can eventually flow into the rest of your home. Keeping the fan on may pull more cold air upward, increasing the amount of heating you need to stay warm.

If you’re still trying to decide if you should switch to the fan/on setting, keep in mind that every home and family’s comfort needs are not the same. Leaving the HVAC system’s fan on might work for you if:

Someone in your household suffers from allergies. Allergies and other respiratory conditions can be stressful on the family. Leaving the fan on should help to enhance indoor air quality, helping your family breathe easier.

Your home has hot and cold spots. Lots of homes deal with difficult hot and cold spots that quickly shift to a temperature different from the rest of the house. The fan setting can help minimize these changes by constantly refreshing each room’s airflow.